Heat exchanger and method of manufacturing the same

Abstract

A heat exchanger includes tubes, a core plate connected to the tubes, a tank connected to the core plate to be in communication with the tubes and a sealing member sealing a connecting portion between the core plate and the tank. The core plate has a groove portion including at least a base wall and an inner side wall to define a groove having a loop shape. The sealing member is disposed in the groove portion to be in contact with the inner side wall at least at two opposite locations of the loop shape. Alternatively, the sealing member is disposed in the groove portion to be in contact with at least one of the inner side wall and an outer side wall opposed to the inner side wall, and a substantially middle portion of a width of the sealing member is pressed by a projection of the tank.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Applications No. 2008-106016 filed on Apr. 15, 2008 and No. 2008-106017 filed on Apr. 15, 2008, the disclosure of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a heat exchanger having a sealing structure between a tank and a core plate and a method of manufacturing the heat exchanger.

BACKGROUND OF THE INVENTION

A sealing structure between a tank and a core plate of a heat exchanger is, for example, described in JP-A-58-224298. In the described sealing structure, an elastic sealing member is disposed in an outer peripheral groove of a metal core plate, and is deformed by being compressed by a surface of a peripheral end of a resin tank. Further, the core plate is clamped with the tank such that the sealing member retains a deformed condition between the core plate and the tank.

In such a case, the elastic sealing member is merely placed in the outer peripheral groove of the core plate during an assembling process. Therefore, the elastic sealing member may be displaced from a desirable position, depending on a condition of the core plate, such as an arranged direction of the core plate. If the elastic sealing member is compressed by the peripheral end of the tank under a displaced position, it will be difficult to achieve a sufficient sealing effect.

JP-A-58-224298 also describes an example of compressing the sealing member by a projection formed on an end surface of the peripheral end of the tank. Also in this case, since the sealing member is merely placed in the outer peripheral groove, if the sealing is displaced from a desired position, it may be difficult to maintain a positional relationship between the sealing member and the projection. If the sealing member is compressed by the projection under the displaced position, it is difficult to exhibit a predetermined elastic force. Thus, it will be difficult to achieve a sufficient sealing effect.

SUMMARY OF THE INVENTION

The present invention is made in view of the foregoing matter, and it is an object of the present invention to provide a heat exchanger with a sealing structure capable of holding a sealing member in a predetermined position, thereby to achieve a sufficient sealing effect. It is another object of the present invention to provide a method of manufacturing a heat exchanger with a sealing structure capable of holding a sealing member in a predetermined position, thereby to achieve a sufficient sealing effect. It is further another object of the present invention to provide a heat exchanger with a sealing structure capable of properly elastically deforming a sealing member between a tank and a core plate, thereby to achieve a sufficient sealing effect. It is still another object of the present invention to provide a method of manufacturing a heat exchanger with a sealing structure capable of properly elastically deforming a sealing member between a tank and a core plate, thereby to achieve a sufficient sealing effect.

According to a first aspect of the present invention, a heat exchanger includes a core, a core plate, a tank and a sealing member. The core includes a plurality of tubes. The core plate is connected to the tubes. The tank is connected to the core plate to be in communication with the tubes. The sealing member has a loop shape and is disposed to seal a connecting portion between the core plate and the tank. The core plate has a groove portion including at least a base wall and an inner side wall to define a groove having a loop shape. The sealing member is disposed in the groove portion and is in contact with the inner side wall at least at two opposite locations of the loop shape.

Accordingly, since the loop-shaped sealing member is disposed in the groove portion to be in contact with the inner side wall at least at two opposite location of the loop shape, it can be fixed to the core plate while constricting the inner side wall inwardly. That is, because the sealing member is securely fixed in a predetermined position, a sufficient sealing effect between the core plate and the tank is achieved.

According to a second aspect of the present invention, a heat exchanger includes a core, a core plate, a tank and a sealing member. The core includes tubes. The core plate is connected to the tubes. The tank is connected to the core plate to be in communication with the tubes. The sealing member has a loop shape and is disposed to seal a connecting portion between the core plate and the tank. The core plate has a groove portion including at least a base wall and an inner side wall to define a groove having a loop shape. The sealing member has a width smaller than a width of the groove of the groove portion and is configured such that a whole length thereof under an original condition without being elastically deformed is less than a whole length of the groove, the whole length of the sealing member being defined by a whole length of a longitudinal axis passing through a center of a cross-section of the sealing member, the whole length of the groove being defined by a whole length of a longitudinal axis passing through a center of the width of the groove. The sealing member is fixed to the groove portion in accordance with a restoration force, which is generated by restoring the sealing member from a stretched condition. The sealing member is further pressed against the groove portion by the tank.

Since the sealing member is fixed to the groove portion using the restoration force generated by restoring the sealing member from the stretched condition, a fixing force of the sealing member can be ensured in accordance with the restoration force. Thus, the sealing member can be stably held in a predetermined position on the core plate, and hence the sufficient sealing effect between the core plate and the tank is achieved. In this case, a dimension of the sealing member is determined appropriately in consideration of fixing work to the groove portion and the fixing force to be required. Thus, productivity improves.

According to a third aspect of the present invention, a method of manufacturing a heat exchanger includes: forming a core plate into a predetermined shape including a groove portion defining a loop-shaped groove; assembling the core plate to tubes; preparing a sealing member having a whole length less than a whole length of the groove, the whole length of the sealing member being defined by a whole length of a longitudinal axis passing through a center of a cross-section thereof, the whole length of the groove being defined by a whole length of a longitudinal axis passing through a center of a width of the groove; stretching the sealing member into a predetermined size; placing the sealing member under a stretched condition in the groove portion; attaching the sealing member to the groove portion in accordance with a restoration force caused by removing a stretching force from the sealing member; and fixing a tank to the core plate such that the sealing member is elastically deformed between the tank and the core plate.

Accordingly, the sealing member having the predetermined dimension is prepared, and is fixed to the groove portion in accordance with the restoration force caused by restoring the sealing member from the stretched condition. Thus, a predetermined fixing force for fixing the sealing member to the core plate is ensured and the sealing member can be fixed in the predetermined position. As such, the sufficient sealing effect is achieved and productivity improves.

According to a fourth aspect of the present invention, a heat exchanger includes a core, a core plate, a tank and a sealing member. The core includes a plurality of tubes. The core plate is connected to the tubes. The core plate has a groove portion including an inner side wall and an outer side wall to define a loop-shaped groove therebetween. The tank is connected to the core plate to be in communication with the tubes. The sealing member seals between the core plate and the tank. The sealing member has a loop-shaped body portion having a width less than a width of the groove. The body portion of the sealing member is disposed in the groove portion under a condition of being in contact with at least one of the inner side wall and the outer side wall. The tank has a projection on an end surface opposing to the body portion of the sealing member. The projection presses against a substantially middle portion of the width of the body portion of the sealing member to elastically deform the body portion of the sealing member.

Accordingly, the sealing member is held in the predetermined position in the groove portion, and the substantially middle portion of the width of the body portion is pressed by the projection of the tank. Therefore, a pressing force of the tank is sufficiently transmitted to the sealing member, and thus the sealing member is securely and sufficiently compressed. Accordingly, the sealing member exhibits a sufficient elastic force. In this way, the sealing member can be held in a sufficiently deformed condition, and hence the sufficient sealing effect can be achieved.

According to a fifth aspect of the present invention, a method of manufacturing a heat exchanger includes: forming a core plate into a predetermined shape including a groove portion defining a loop-shaped groove; assembling the core plate to tubes; attaching a sealing member in the groove portion such that the sealing member contacts at least one of an inner side wall and an outer side wall of the groove portion; and fixing a tank to the core plate such that a projection of an end surface of the tank is pressed against a substantially middle portion of a width of the sealing member to elastically deform the sealing member, thereby sealing between the core plate and the tank with the sealing member.

Accordingly, the sealing member is held in the predetermined position in the groove portion, and is elastically deformed by pressing the substantially middle portion of the width thereof by the projection of the tank. Thus, the pressing force of the tank is sufficiently transmitted to the sealing member, and hence the sealing member is securely and sufficiently compressed. Accordingly, since the sealing member is properly elastically deformed, the sufficient sealing effect can be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings, in which like parts are designated by like reference numbers and in which:

FIG. 1 is a plan view of a radiator according to a first embodiment of the present invention;

FIG. 2 is an end view of the radiator when viewed along an arrow II in FIG. 1;

FIG. 3 is a cross-sectional view taken along a line III-III in FIG. 1;

FIG. 4 is a cross-sectional view taken along a line IV-IV in FIG. 2;

FIG. 5 is a plan view of a core plate of the radiator in a condition where a sealing member is disposed in a groove portion according to the first embodiment;

FIG. 6A is a plan view of an example of the sealing member according to the first embodiment;

FIG. 6B is a plan view of another example of the sealing member according to the first embodiment;

FIG. 7 is a cross-sectional view taken along a line VII-VII in FIG. 5;

FIG. 8 is a cross-sectional view taken along a line VIII-VIII in FIG. 5;

FIG. 9 is a cross-sectional view of a part of the core plate for showing an example of the sealing member disposed adjacent to an inner side wall of the groove portion according to the first embodiment;

FIG. 10 is a cross-sectional view of a part of the core plate for showing an example of a sealing structure in which a projection of a tank substantially coincides with a center of the sealing member according to the first embodiment;

FIG. 11 is a cross-sectional view of a part of the core plate for showing an example of a sealing structure with a sealing member having a circular cross-section and a tank without having a projection according to the first embodiment;

FIG. 12 is a perspective view of the core plate formed by a core plate forming step according to the first embodiment;

FIG. 13 is a cross-sectional view taken along a line XIII-XIII in FIG. 12;

FIG. 14 is a perspective view of the sealing member before stretched by a sealing member stretching step according to the first embodiment;

FIG. 15 is a perspective view for showing the sealing member stretching step according to the first embodiment;

FIG. 16 is a perspective view for showing a sealing member placing step according to the first embodiment;

FIG. 17 is a cross-sectional view taken along a line XVII-XVII in FIG. 16;

FIG. 18 is a perspective view for showing a sealing member attaching step according to the first embodiment;

FIG. 19 is a cross-sectional view taken along a line XIX-XIX in FIG. 18;

FIG. 20 is a perspective view for showing a tank attaching step according to the first embodiment;

FIG. 21 is a perspective view of the tank attached to the core plate according to the first embodiment;

FIG. 22 is a perspective view for showing a tank fixing step according to the first embodiment;

FIG. 23A is a cross-sectional view of an example of a sealing structure in which a long side of a sealing member is in contact with an inner side wall of a groove portion of a core plate according to a second embodiment of the present invention;

FIG. 23B is a cross-sectional view of an example of the sealing structure in which the long side of the sealing member is in contact with an outer side wall of the groove portion according to the second embodiment;

FIG. 24A is a cross-sectional view of an example of the sealing structure in which a short side of the sealing member is in contact with the inner side wall of the groove portion according to the second embodiment;

FIG. 24B is a cross-sectional view of an example of the sealing structure in which the short side of the sealing member is in contact with the outer side wall of the groove portion according to the second embodiment;

FIG. 25 is a cross-sectional view of an example of the sealing structure in which a portion of the sealing member is disposed without contacting the inner side wall and the outer side wall of the groove portion according to the second embodiment;

FIG. 26 is a plan view of a sealing member according to a third embodiment of the present invention;

FIG. 27 is a plan view of a core plate in which the sealing member of FIG. 26 is disposed according to the third embodiment; and

FIG. 28 is a cross-sectional view taken along a line XXVIII-XVIII in FIG. 27.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENT

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. Like parts are designated by like reference numbers, and a description thereof will not be repeated.

First Embodiment

A heat exchanger has a sealing structure for sealing between a tank and a core plate. The heat exchanger performs heat exchange between an internal fluid as a heat exchange medium flowing inside of tubes and an external fluid flowing outside of the tubes. The heat exchanger is, for example, a radiator, an inter cooler and the like.

A first embodiment will be described hereinafter with reference to FIGS. 1 to 22. In the present embodiment, the heat exchanger is, for example, a radiator 1 that performs heat exchange between engine cooling water for cooling an engine (not shown) as the internal fluid and air as the external fluid.

In the drawings, an arrow X denotes a longitudinal direction of a tank and a core plate. The direction X corresponds to a tube stacking direction in which tubes are stacked. An arrow Y denotes a direction perpendicular to the longitudinal direction of the tank X. The direction Y corresponds to a width direction of the tank and the core plate in which a width of the tank and the core plate is measured. The direction Y also corresponds to a flow direction of the external fluid.

The radiator generally includes an upper tank 2, a core section, and a lower tank 3. The core section includes an upper core plate 4, a core 8 and a lower core plate 5. For example, each of components of the radiator 1 can be made of a metal, such as aluminum, aluminum alloy and the like. The components are joined to each other, such as by brazing. Also, each component can be provided by a clad member, surfaces of which are cladded with a brazing material, for example.

The core 8 includes tubes 8a and heat radiation fins 8b. The tubes 8a and the fins 8b are joined to each other by brazing. The core 8 serves as a heat exchanging part for radiating heat of the engine cooling water flowing inside of the tubes 8a to the air through walls of the tubes 8a and fins 8b.

For example, the radiator 1 is mounted in a vehicle such that the tubes 8a extend in a generally up and down direction. The tubes 8a are arranged at predetermined intervals in the longitudinal direction X of the core plate 4. The fins 8b are disposed between the tubes 8a along a longitudinal direction of the tubes 8a. That is, the tubes 8a and the fins 8b are alternately stacked.

The tubes 8a have a flat tubular shape. For example, each of the tubes 8a is constructed by joining plate members each having a predetermined shape. The fins 8b are, for example, corrugate fins produced by shaping a plate into a wave form. The fins 8b can be formed with louvers for improving a coefficient of heat transfer. For example, the louvers are formed by cutting and moving portions of a wall of the tin 8b to define a predetermined angle with respect to the flow direction Y of the external fluid.

The upper tank 2 and the lower tank 3 are made of a resin or a metal, such as aluminum. The upper tank 2 and the lower tank 3 have a substantially similar shape. The upper tank 2 has a long container shape having an opening on one side. Likewise, the lower tank 3 has a long container shape having an opening on one side.

The radiator 1 is provided with an inlet pipe 21 and an outlet pipe 31. The inlet pipe 21 is coupled to the upper tank 2 for introducing the engine cooling water into the radiator 1. The outlet pipe 31 is coupled to the lower tank 3 for discharging the engine cooling water from the radiator 1. For example, the inlet pipe 21 is located adjacent to an end (e.g., left end in FIG. 1) of the upper tank 2. The outlet pipe 31 is located adjacent to an opposite end (e.g., right end in FIG. 1) of the lower tank 3 with respect to the longitudinal direction X.

The inlet pipe 21 and the outlet pipe 31 have a substantially similar shape. For example, the inlet pipe 21 and the outlet pipe 31 each have a cylindrical shape. The inlet pipe 21 is coupled to an opening formed on a side wall of the upper tank 2, and the outlet pipe 31 is coupled to an opening formed on a side wall of the lower tank 3. The inlet pipe 21 and the outlet pipe 31 are brazed to the upper tank 2 and the lower tank 3, respectively. In the radiator 1, the engine cooling water flows through the upper tank 2, the tubes 8a, and the lower tank 3.

The upper core plate 4 is formed by shaping a metal plate member into a predetermined shape, such as a substantially rectangular shape. Here, the term “substantially rectangular shape” includes an exactly rectangular shape and a substantially rectangular shape. The upper core plate 4 is made of a metal, such as aluminum, aluminum alloy or the like.

The upper core plate 4 is integrated with the upper tank 2. The upper core plate 4 is joined to the upper tank 2 to cover the opening of the upper tank 2, thereby to define a tank inner space between the upper core plate 4 and the upper tank 2.

The upper core plate 4 is formed with tube insertion holes 4c with the same number as the number of the tubes 8a. The tube insertion holes 4c are formed at predetermined intervals in the longitudinal direction X. The upper ends of the tubes 8a are inserted in the tube insertion holes 4c and outer peripheries of the upper ends of the tubes 8a are joined to perimeters of the tube insertion holes 4c by brazing. Thus, the tubes 8a are fixed to the upper core plate 4.

The core plate 4 has a groove portion 4a on a periphery of the tube insertion holes 4c. The groove portion 4a defines a loop-shaped groove surrounding the periphery of the tube insertion holes 4c. The groove portion 4a has at least a bottom wall 4f defining a bottom of the groove and an inner side wall 4d that is located more to the inside of the upper core plate 4 than the bottom wall 4f. The bottom wall 4f is opposed to an outer peripheral portion 2a of the upper tank 2 through a sealing member 10.

The groove portion 4a is provided entirely along the vicinity of an outer peripheral edge of the upper core plate 4. The groove portion 4a further includes an outer side wall 4e extending from the bottom wall 4f. The outer side wall 4e is spaced from the inner side wall 4d by a width of the groove. That is, the outer side wall 4e is connected to the inner side wall 4d through the bottom wall 4f. For example, the inner side wall 4d and the outer side wall 4e extend substantially perpendicularly from the bottom wall 4f. The inner side wall 4d, the outer side wall 4e and the bottom wall 4f provide the groove between them.

As shown in FIG. 5, the groove portion 4a has a substantially rectangular outline. The groove of the groove portion 4a includes a pair of long-side portions 41 and a pair of short-side portions 42. The long-side portions 41 are parallel to each other and extend in the longitudinal direction X. The short-side portions 42 are parallel to each other and extend in the width direction Y. The long-side portions 41 intersect the short-side portions 42 at corner portions 43. The long-side portions 41 are also referred to as long-side portions of the upper core plate 4, and the short-side portions 42 are also referred to as short-side portions of the upper core plate 4.

The upper core plate 4 has nail portions 4b partly projecting from upper edge of the outer side wall 4e. The nail portions 4b are in the form of projections and are arranged at predetermined intervals along the upper edge of the outer side wall 4e. Thus, recesses are provided between the adjacent nail portions 4b.

The nail portions 4b are folded over a flange portion 2c of the upper tank 2 after the upper tank 2 is attached to the upper core plate 4. Thus, the nail portions 4b serve as fixing portions for fixing the upper core plate 4 to the upper tank 2.

The lower core plate 5 has the substantially similar shape and structure as those of the upper core plate 4. Also, the lower core plate 5 is made of the similar material as that of the upper core plate 4. The lower core plate 5 is integrated with the lower tank 3. The lower core plate 5 is joined with the lower tank 3 to cover the opening of the lower tank 3.

The lower core plate 5 is formed with tube insertion holes with the same number as the number of the tubes 8a. The tube insertion holes of the lower core plate 5 are arranged at predetermined intervals in the longitudinal direction X.

The lower ends of the tubes 8a are inserted in the tube insertion holes of the lower core plate 5, and outer peripheries of the lower ends of the tubes 8a are brazed to perimeters of the tube insertion holes of the lower core plate 5. Thus, the tubes 8 are coupled to and fixed to the lower core plate 5.

The lower core plate 5 has a groove portion, similar to the groove portion 4a of the upper core plate 4. The groove portion is formed to surround an outer periphery of the tube insertion holes. Further, the lower core plate 5 has nail portions projecting from an edge of an outer side wall of the groove portion. The nail portions serve as fixing portions for fixing the lower core plate 5 to the lower tank 3 by being bent inwardly, similar to the nail portions 4b of the upper core plate 4.

In this way, the upper core plate 4 and the lower core plate 5 are integrated with the opposite ends of the tubes 8a. In the core 8, the tubes 8a and the fins 8b are alternately stacked in the longitudinal direction X, that is, in the stacking direction X. The core part 8 further includes side plates 6, 7 along ends of the stack of tubes 8a and fins 8b with respect to the stacking direction X for reinforcing and holding the stack of tubes 8a and fins 8b.

As shown in FIGS. 3 and 4, the sealing member (e.g., packing) 10 is disposed between the outer peripheral portion 2a of the upper tank 2, which defines the opening of the upper tank 2, and the groove portion 4a of the upper core plate 4. The outer peripheral portion 2a of the upper tank 2 and the groove portion 4a of the upper core plate 4 provide a connecting portion between the upper tank 2 and the upper core plate 4.

The sealing member 10 is elastically deformed between an end surface of the outer peripheral portion 2a and the bottom wall 4f of the groove portion 4a and is closely in contact with the upper tank 2 and the upper core plate 4 to seal therebetween. In other words, the sealing member 10 seals between the upper tank 2 and the upper core plate 4, thereby to restrict leakage of the engine cooling water from the upper tank 2. The upper tank 2 has the flange portion 2c along its outer peripheral end. The flange portion 2c is integral with the outer peripheral portion 2a and extends outwardly.

The sealing member 10 has a loop shape and is disposed to constrict a tubular portion formed on an inner side of the groove portion 4a in accordance with its inward contraction force. The sealing member 10 generates a predetermined constricting force so that it is not separated from the upper core plate 4 at an initial stage during assembling of the radiator 1. As a result, the sealing member 10 is disposed in the groove portion 4a under a condition of contacting the inner side wall 4d at least at two opposite locations of the loop-shape of the groove portion 4a.

For example, the sealing member 10 can be disposed to contact the inner side wall 4d at two opposite sides of the substantially rectangular shape of the groove portion 4a or at diagonally opposite corner portions 43. As another example, the sealing member 10 can be disposed to contact the inner side wall 4d at all four sides of the substantially rectangular shape of the groove portion 4a or/and at all the four corner portions 43.

Although the sealing member 10 can be disposed to contact also the outer side wall 4e of the groove portion 4a, it is preferable to contact only the inner side wall 4d in one example. The sealing member 10 can be disposed to contact the entirety of the inner side wall 4d. The sealing member 10 can be disposed to contact almost the entirety of the inner side wall 4d. The inner side wall 4d can be partly formed with recesses so that there are non-contact portion with the sealing member 10. For example, the projection 2b has a curved top end. For example, the projection 2b has a substantially semi-circular cross-section.

The upper tank 2 has a projection 2b projecting from the end surface of the outer peripheral portion 2a toward the sealing member 10. For example, the projection 2b is formed entirely along the end surface of the outer peripheral portion 2a. The projection 2b is provided to partly increase a pressing force against an upper surface of the sealing member 10, thereby to improve a sealing effect of the sealing member 10.

In an example shown in FIG. 4, the sealing member 10 is disposed such that short-sides 12 of the sealing member 12 are located closer to the inner side wall 4d than the outer side wall 4e in the short-side portions 42. In other words, the sealing member 10 is disposed such that a center of a cross-section of the short-sides 12 is closer to the inner side wall 4d than a center of a width of the short-side portions 42 of the groove portion 4.

FIG. 5 shows a condition where the sealing member 10 is mounted to the upper core plate 4. As shown in FIG. 5, the sealing member 10 is disposed entirely along the groove portion 4a. The sealing member 10 is disposed in the groove portion 4a such that inner surfaces 11a of the long-sides 11 or inner surfaces 12a of the short-sides 12 contact the inner side wall 4d. Thus, the sealing member 10 is held in the groove portion 4a in a displacement-restricted manner.

Next, a structure of the sealing member 10 will be described more in detail. The sealing member 10 is an elastic member having a loop shape with a predetermined compression rate. The sealing member 10 has a width A smaller than a width B of the groove portion 4a, as shown in FIGS. 3 and 4.

For example, the sealing member 10 is made of a rubber, such as ethylene propylene rubber (EPDM), silicon-base rubber and the like. Here, the loop shape of the sealing member 10 is not limited to a circular or annular shape, but includes any continuous shapes. For example, the sealing member 10 is formed into a shape corresponding to the shape of the groove portion 4a of the upper core plate 4 and the groove portion of the lower core plate 5.

The sealing member 10 is formed into a shape to be adapted to the shape of the groove portion to which the sealing member 10 is disposed. For example, in a case where the groove portion in which the sealing member 10 is disposed has a rectangular loop shape, the sealing member 10 having a rectangular shape can be employed. Alternatively, the sealing member 10 having another loop shape, such as a circular shape, an elliptic shape and the like, can be employed to the rectangular loop-shaped groove portion.

The sealing member 10 has an outer shape smaller than the groove portion 4a of the core plate 4. For example, a whole length of the sealing member 10 under a natural condition (original condition) without being affected by an external force is less than a whole length of the groove portion 4a. Here, the whole length of the sealing member 10 is defined by a whole length of a longitudinal axis of the sealing member 10 passing through a center of a cross-section thereof, and the whole length of the groove portion 4a is defined by a whole length of a longitudinal axis of the groove portion 4a. The longitudinal axis of the groove portion 4a is defined by a line passing through a center of a width of the bottom wall 4f.

Since the sealing member 10 has elasticity, the sealing member 10, which has the whole length less than the whole length of the groove portion 4a under the natural condition, can be placed in the groove portion while being stretched. After the sealing member 10 is placed in the groove portion 4a under a stretched condition, when a stretching force is removed from the sealing member 10, the sealing member 10 is brought into contact with the inner side wall 4d in accordance with a restoration force thereof trying to return to the original condition. Thus, the sealing member 10 can be held by the core plate 4.

FIGS. 6A and 6B show examples of the sealing member 10 having the substantially rectangular shape in which the whole length is less than the whole length of the groove portion 4a under the natural condition.

In the example of FIG. 6A, the short-sides 12 of the sealing member 10 has a width Dp less than a width D of the short-side portions 42 of the groove portion 4a under the natural condition. In other words, a dimension of the sealing member 10 in the width direction Y under the natural condition is less than a dimension of the groove portion 4a in the width direction Y. In FIG. 6A, a double-dashed chain line shows the sealing member 10 stretched into a width corresponding to the width D of the groove portion 4a.

In the example of FIG. 6B, the long-sides 11 of the sealing member 10 has a length Lp less than a length L of the long-side portions 41 of the groove portion 4a under the natural condition. In other words, a dimension of the sealing member 10 in the longitudinal direction X under the natural condition is less than a dimension of the groove portion 4a in the longitudinal direction X. In FIG. 6B, a double-dashed chain line shows the sealing member 10 stretched into a length corresponding to the length L of the groove portion 4a.

When the sealing member 10 of FIG. 6A is employed, the sealing member 10 is stretched mainly in the width direction Y to be placed in the groove portion 4a. In this case, the sealing member 10 contracts inwardly, such as mainly in the width direction Y, as shown by arrows in FIG. 7. Thus, the inner surfaces 11a of the long-sides 11 are brought into contact with the inner side wall 4d and hence the sealing member 10 is held by the inner side wall 4a. Further, the sealing member 10 is pressed against the groove portion 4a by the outer peripheral portion 2a of the upper tank 2 in a condition that the inner surfaces 11a are in contact with the inner side wall 4d. In this way, the sealing member 10 can be fixed.

FIG. 7 shows a cross-section of the sealing structure when taken along a line VII-VII in FIG. 5. For example, the sealing member 10 is disposed such that the long-sides 11 are located closer to the inner side wall 4d than the outer side wall 4e. In other words, the sealing member 10 is disposed such that the center of the cross-section of the long-sides 11 is located more to an inner side of the core plate 4 than the center of the cross-section of the long-side portions 41 of the groove portion 4a. In this case, as shown in FIG. 9, a line 14 passing through the center of the cross-section of the long-sides 11 is located closer to the inner side wall 4d than a line 44 passing through the center of the cross-section of the long-side portions 41. FIG. 9 shows a condition where the sealing member 10 is located closer to the inner side wall 4d of the groove portion 4a.

In the case where the sealing member 10 shown in FIG. 6B is employed, the sealing member 10 is stretched mainly in the longitudinal direction X to be placed in the groove portion 4a. In this case, the sealing member 10 contracts inwardly, such as mainly in the longitudinal direction X. Thus, the inner surfaces 12a of the short-sides 12 are brought into contact with the inner side wall 4d of the groove portion 4a and hence the sealing member 10 is held by the inner side wall 4d. Further, the sealing member 10 is pressed against the groove portion 4a by the outer peripheral portion 2a of the upper tank 2 in a condition where the inner surfaces 12a of the short-sides 12 are in contact with the inner side wall 4d. In this way, the sealing member 10 can be fixed.

FIG. 8 shows the corner portion 13 of the sealing member 10 when taken along a line VIII-VIII in FIG. 5. As shown in FIG. 8, the sealing member 10 can be configured to contract inwardly at the corner portions 13 in accordance with the elasticity. Thus, the sealing member 10 is held in the groove portion 4a in a condition that the inner surfaces of the corner portions 13 are closely in contact with the inner side wall 4d. In this case, the sealing member 10 is fixed by being pressed against the groove portion 4a by the outer peripheral portion 2a of the upper tank 2 in a condition that the inner surfaces of the corner portions 13 are in contact with the inner side wall 4d.

In this case, the sealing member 10 is arranged such that the corner portions 13 are located closer to the inner side wall 4d than the outer side wall 4e. In other words, at the corner portions 13, the longitudinal axis of the sealing member 10 is located more to the inside of the core plate 4, i.e., the inner side wall 4d, than the longitudinal axis of the groove portion 4a.

To make the sealing member 10 contact the inner side wall 4d of the groove portion 4a at the corner portions 13, for example, the sealing member 10 can be formed such that a radius of curvature of the inner surface of the corner portion 13 under the natural condition is greater than a radius of curvature of the inner side wall 4d of the corner portion 43. After such sealing member 10 is stretched and placed in the groove portion 4a, when the stretching force is removed from the sealing member 10, the sealing member 10 contracts inwardly due to the restoration force trying to restore to the original condition. In this case, the inner surfaces of the corner portions 13 are brought into contact with the corner portions of the inner side wall 4d prior to the other portions. Thus, the sealing member 10 is held by the upper core plate 4 by the close contact at the corner portions 13.

The sealing member 10 can be pressed by the outer peripheral portion 2a of the upper tank 2 such that the projection 2b coincides with the line 14 passing through the longitudinal axis of the sealing member 10. FIG. 10 shows an example where the sealing member 10 is to be pressed by the outer peripheral portion 2a in a condition where the projection 2b coincides with the line 14.

In an example of FIG. 10, the sealing member 10 is arranged such that the center of the cross-section of the sealing member 10 is closer to the inner side wall 4d of the groove portion 4a. Further, the upper tank 2 is arranged to the upper core plate 4 such that the projection 2b substantially coincides with the line 14. Here, the term “substantially coincide” includes a condition of “exactly coinciding” also. For example, the projection 2b is formed closer to an inner edge of the end surface of the outer peripheral portion 2a than an outer edge of the end surface of the outer peripheral portion 2a.

In this case, the sealing member 10 can be securely pressed by the projection 2b. Therefore, the sealing member 10 can be deformed to expand toward the outer side wall 4e while contacting the inner side wall 4d and the bottom wall 4f. That is, because the sealing member 10 can be properly held without displacing during the assembling, a clearance between the inner side wall 4d and the bottom wall 4f of the upper core plate 4 and the outer peripheral portion 2a of the upper tank 2 is securely sealed y the sealing member 10. Accordingly, a stable sealing effect is achieved.

In a case where the sealing member 10 has a rectangular cross-section, a contact area with the inner side wall 4d and the bottom wall 4f of the upper core plate 4 and the outer peripheral portion 2a of the upper tank 2 can be increased. In this case, the contact between the upper core plate 4 and the upper tank 2 improves. As such, the sealing effect improves. Also, as shown in FIG. 10, a depth h of the groove portion 4a is equal to or greater than a thickness t of the sealing member 10.

The sealing member 10 can have any cross-sectional shape other than the rectangular shape. For example, as shown in FIG. 11, the sealing member 10 can have a rounded cross-section, such as a substantially circular cross-section, a circular cross-section, an elliptic cross-section and the like. In this case, the tank 2 does not have the projection 2b. That is, the end surface of the outer peripheral portion 2a of the tank 2 is substantially flat. The sealing member 10 is arranged in the groove portion 4a such that a center of the cross-section of the sealing member 10 is located closer to the inner side wall 4d. The sealing member 10 is pressed against the groove portion 4a by the flat end surface of the outer peripheral portion 2a of the upper tank 2.

In this case, the sealing member 10 is securely pressed by the end surface of the outer peripheral portion 2a of the upper tank 2. At this time, the sealing member 10 is deformed to expand toward the outer side wall 4e while contacting the inner side wall 4d. As such, it is less likely that the sealing member 10 will be displaced during the assembling. Thus, the clearance between the inner side wall 4d and the bottom wall 4f of the upper core plate 4 and the outer peripheral portion 2a of the upper tank 2 can be properly sealed with the sealing member 10. A desirable sealing effect can be achieved.

Next, a flow of the cooling water in the radiator 1 will be described. The cooling water flowing out from the engine flows in the upper tank 2 of the radiator 1 through the inlet pipe 21. The cooling water is then introduced into the tubes 8a and then collected in the upper tank 3. Thereafter, the cooling water flows out from the lower tank 3 through the outlet pipe 31 and returns to the engine. While passing through the tubes 8a, the cooling water releases heat to the air flowing outside of the tubes 8a. Thus, the cooling water is cooled.

Hereinafter, advantageous effects of the radiator 1 of the present embodiment will be described. In the present embodiment, since the sealing structure between the lower core plate 5 and the lower tank 3 is similar to the sealing structure between the upper core plate 4 and the upper tank 2. Therefore, the advantageous effects will be described mainly in association with the sealing structure between the upper core plate 4 and the upper tank 2. Also, the sealing structure of the present embodiment can be employed in a heat exchanger having a single tank at one of ends of a core.

In the present embodiment, the radiator 1 includes the core 8 with the tubes 8a, the upper core plate 4, the lower core plate 5, the upper tank 2, the lower tank 3 and the sealing members 10 having the loop shape. The upper core plate 4 and the lower core plate 5 are connected to the ends of the tubes 8a to make communication with the tubes 8a. The upper tank 2 is coupled to the upper core plate 4, and the lower tank 3 is coupled to the lower core plate 5. The sealing members 10 are correspondingly disposed in the connecting portions between the upper and lower tanks 2, 3 and the upper and lower core plates 4, 5 for sealing therebetween.

The upper core plate 4 has the groove portion 4a including at least the bottom wall 4f and the inner side wall 4d and defining the loop-shaped groove. The sealing member 10 is disposed in the groove of the groove portion 4a to contact the inner side wall 4d at least at two opposite locations of the loop-shape.

The sealing member 10 constricts the inner side wall 4d at least at two opposite locations due to its elastic force. In this condition, the sealing member 10 exerts a predetermined constriction force to the inner side wall 4d without being separated from the upper core plate 4. Thus, the sealing member 10 is held by the upper core plate 4.

Accordingly, the sealing member 10 is securely fixed in a predetermined position between the upper tank 2 and the upper core plate 4, thereby to achieve the sufficient sealing effect. The sealing between the lower core plate 5 and the lower tank 3 can be provided in the similar manner, and thus the similar effects are achieved.

The sealing member 10 seals the connecting portion between the upper tank 2 and the upper core plate 4 in the elastically deformed condition due to the pressing force from the upper tank 2. The sealing member 10 has the width A smaller than the width B of the groove portion 4a of the upper core plate 4. The whole length of the sealing member 10 under the natural condition without being elastically deformed is less than the whole length of the groove portion 4a. This sealing member 10 is placed in the groove portion 4a while being stretched from the natural condition, and then is fixed to the groove portion 4a in accordance with its restoration force. In this condition, the sealing member 10 is pressed against the groove portion 4a by the upper tank 2.

That is, the sealing member 10 having a predetermined dimension with respect to the groove portion 4a is prepared. Then, the sealing member 10 is fixed to the groove portion 4a using its restoration force. Therefore, the sealing member 10 can be fixed to the groove portion 4a with a predetermined fixing force generated in accordance with the restoration force. Therefore, it is less likely that the sealing member 10 will be easily displaced during a manufacturing process. In other words, since the sealing member 10 can be stably held in the predetermined position during the manufacturing process, arrangement directions of the components of the radiator 1, that is, assembling directions of the radiator 1 during the manufacturing process are not limited.

The dimension of the sealing member 10 can be determined appropriately in consideration of workability on attaching to the groove portion 4a and the compression rate of the sealing member 10. Accordingly, the sealing effect of the sealing member 10 improves while improving the productivity.

The groove portion 4a has the substantially rectangular loop shape including the pair of long-side portions 41 and the pair of short-side portions 42 intersecting the long-side portions 41 through the corner portions 43. In one example, the sealing member 10 is disposed in the groove portion 4a such that one of the long-sides 41 and the short-sides 42 are in contact with the inner side wall 4d due to the restoration force. In this condition, the sealing member 10 is pressed by the tank 2.

In this case, the sealing member 19 is fixed to the groove portion 4a at the long-sides 11 or the short-sides 12. Therefore, the positioning and fixing of the sealing member 10 can be conduced by considering the restoration force at least in one of the longitudinal direction X and the width direction Y. Accordingly, productivity further improves.

In the case where the sealing member 10 is pressed by the tank 2 under the condition where the short-sides 42 are in contact with the inner side wall 4d of the groove portion 4a by the restoration force, the contact area between the sealing member 10 and the inner side wall 4d is smaller than that of the case where the sealing member 10 is pressed by the tank 2 under the condition where the long-sides 41 are in contact with the inner side wall 4d of the groove portion 4a. In this case, therefore, a surface pressure applied to the sealing member 10 can be increased. As such, the fixing force of the sealing member 10 is ensured, and thus the sealing member 10 is stably fixed in the predetermined position.

In one example, the sealing member 10 is pressed by the tank 2 under the condition where the corner portions 13 contact the inner side wall 4d due to the restoration force.

In this case, the sealing member 10 is brought into contact with the corner portions 43 of the groove portion 4a using its restoration force. Therefore, the shape of the sealing member 10 is not limited to the rectangular loop shape. In other words, the sealing members 10 having any looped shapes, other than the rectangular shape, can be stably fixed to the groove portion 4a.

In the case where the whole length of the rectangular loop-shaped sealing member 10 under the natural condition is set less than the whole length of the groove portion 4a, the sealing member 10 in which the pair of long-sides 11 are shorter than the long-side portions 41 of the groove portion 4a under the natural condition can be employed, as one example. In this case, the sealing member 10 is placed in the groove portion 4a while being stretched in the longitudinal direction X. Thus, the sealing member 10 is fixed to the groove portion 4a using the restoration force in the longitudinal direction X. Accordingly, the positioning of the sealing member 10 with respect to the groove portion 4a is easily conducted, and fixing work of the sealing member 10 improves.

As another example of the sealing member 10 having the whole length less than the whole length of the groove portion 4a under the natural condition, the sealing member 10 in which the pair of short-sides 12 are shorter than the short-side portions 42 of the groove portion 4a under the natural condition can be employed. In this case, the sealing member 10 is placed in the groove portion 4a while being stretched in the width direction Y. Thus, the sealing member 10 is fixed to the groove portion 4a using the restoration force in the width direction Y. Also in this case, the positioning of the sealing member 10 with respect to the groove portion 4a is easily conducted, and fixing work of the sealing member 10 improves.

In the case where the sealing member 10 is fixed to the groove portion 4a such that the center of the cross-section thereof is located closer to the inner side wall 4d than the center of the cross-section of the groove portion 4a, a clearance is provided between an outer surface of the sealing member 10 and the outer side wall 4e of the groove portion 4a. Therefore, the sealing member 1 can be easily mounted to the groove portion 4a.

For example, the groove portion 4a further includes the outer side wall 4e extending perpendicularly from the bottom wall 4f. The inner side wall 4d also extends perpendicularly from the bottom wall 4f and opposed to the outer side wall 4e. Thus, the groove of the groove portion 4a is provided by the outer side wall 4e, the bottom wall 4f and the inner side wall 4d. The groove portion 4a has the substantially U-shape. In this case, the sealing member 10 can be easily brought into contact with the walls of the groove portion 4a. Thus, the sealing member 10 can be stably disposed in the groove portion 4a.

In the case where the depth h of the groove portion 4a is equal to or greater than the thickness t of the sealing member 10, a surface of the sealing member 10 can be brought into contact with the wall of the groove portion 4a entirely in the direction in which the thickness of the sealing member 10 is measured.

In the case where the sealing member 10 has the rectangular cross-sectional shape, the contact area with the groove portion 4a increases. Therefore, a fixing condition of the sealing member 10 before being pressed by the tank 2 improves. Accordingly, the sealing member 10 can be easily arranged in the predetermined position.

Next, a method of manufacturing the radiator 1 of the present embodiment will be described with reference to FIGS. 12 to 22. The method generally includes a core plate forming step, a core section assembling step, a brazing step, a sealing member stretching step, a sealing member placing step, a sealing member attaching step and a tank attaching step. In FIGS. 16 to 22, the core part 8 is not illustrated for convenience of illustration.

The lower core plate 5 has the similar structure as the upper core plate 4, and the sealing structure between the lower core plate 5 and the lower tank 3 is constructed in a similar manner to that between the upper core plate 4 and the upper tank 2. Therefore, the method will be hereinafter described mainly in association with the sealing structure between the upper tank 2 and the upper core plate 4.

In the core plate forming step, the upper core plate 4 having the predetermined shape is formed, as shown in FIGS. 12 and 13. For example, the upper core plate 4 is formed by shaping a plate member using a pressing machine, a rolling machine and the like. In this case, the upper core plate 4 is exemplarily formed such that the dimension of the groove portion 4a with respect to the longitudinal direction X is greater than the dimension of the sealing member 10 under the natural condition with respect to the longitudinal direction X.

In the core section assembling step, the core section is preliminarily assembled. For example, the tubes 8a and the fins 8b are alternately stacked. The upper ends of the tubes 8a are inserted in the tube insertion holes 4c, and the lower ends of the tubes 8a are inserted in the tube insertion holes of the lower core plate 5. Further, the side plates 6, 7 are attached to the ends of the stack of tubes 8a and fins 8b to hold the stack of tubes 8a and fins 8b in the longitudinal direction X. Thus, the core section is preliminarily assembled.

In the brazing step, the core section, which has been preliminarily assembled as above, is brazed. For example, flux is applied to the preliminarily assembled core section, and then the preliminarily assembled core section is heated in a furnace to braze joining portions between the components. As such, the core section is produced.

In the brazing step, the preliminarily assembled core section is placed in the furnace in a condition being held by a jig. The inside of the furnace is under atmosphere of such as nitrogen gas and inactive gas. The inside of the furnace is heated to a brazing temperature to melt a brazing material on the components. Thus, the brazing material is melted and spread over the joining portions between the components.

When the core section is removed from the furnace, the brazing material is solidified. Thus, the components of the core section are integrally joined with one another. When the core section is further cooled to the ordinary temperature, the components are joined with one another with sufficient strength. As such, the core section having the sufficient strength is produced.

In the sealing member stretching step, the sealing member 10 having the above-discussed predetermined shape (e.g., FIG. 14) is stretched into a predetermined size, as shown in FIG. 15. Here, the whole length of the sealing member 10 under the natural condition, that is, before stretched, is less than the whole length of the groove portion 4a of the upper core plate 4. Further, as one example, the dimension Lp of the sealing member 10 under the natural condition is less than the dimension L of the groove portion 4a with respect to the longitudinal direction X.

In the sealing member stretching step, the sealing member 10 is laid in a predetermined position, and then four jigs 50, 51 are arranged to the sealing member 10 for stretching the sealing member 10. For example, the four jigs 51, 52 are moved downwardly and arranged in the insides of the corner portions 13 of the sealing member 10. Two jigs 50 are arranged to contact the inner surfaces of the corner portions 13 at one end (e.g., left end in FIG. 15) of the sealing member 10. The other two jigs 51 are arranged to contact the inner surfaces of the corner portions 13 at an opposite end (e.g., right end in FIG. 15) of the sealing member 10.

Each of the jigs 50, 51 has a substantially rectangular shape having a length in an applying direction (inserting direction) in which the jig 50, 51 is applied to the sealing member 10. Further, the jig 50, 51 has an outer surface having a shape corresponding to the shape of the inner surface of each corner portion 13. For example, the outer surface of the jig 50, 51 defines a curved surface. For example, all the jigs 50, 51 are the identical members, and have the same shape.

To stretch the sealing member 10 into the predetermined size, the jigs 50 and the jigs 51 are moved in opposite directions with respect to the longitudinal direction X such that an overall distance between the jigs 50 and the jigs 51 becomes substantially the dimension L. Then, the jigs 50, 51 are held in a stretched position (separated position) such that the long-sides 11 of the sealing member 10 are retained under stretched conditions.

In this case, the sealing member 10 is stretched such that a distance between axes S1 of the short-sides 12 increases from the dimension Lp to the dimension L. That is, the sealing member 10 is stretched in the longitudinal direction by a predetermined dimension (L-Lp).

In the sealing member placing step, the sealing member 10 is placed in the groove of the groove portion 4a. As shown in FIG. 16, the core plate 4 is laid such that the groove portion 4a faces generally upward. The sealing member 10, which has been stretched under the above condition, is moved down and placed in the groove portion 4a. Here, the sealing member 10 is under a condition where an outward operation force against the inward contraction force is applied by the jigs 50, 51, and a lower surface of the sealing member 10 is not in contact with or slightly in contact with the bottom wall 4f of the groove portion 4a, as shown in FIG. 17. That is, the sealing member 10 is under a condition without being affected or bound by the groove portion 4a.

In the sealing member attaching step, the sealing member 10 is released from the above stretched condition and is attached to the groove portion 4a.

As shown in FIGS. 18 and 19, pressing pins 52, 53 are butted to the top of the sealing member 10, which is held under the stretched condition by the jigs 50, 51, to press down the sealing member 10. Thus, the bottom surface of the sealing member 10 is brought into contact with the bottom wall 4f of the groove portion 4. Further, the jigs 50, 51 are removed from the sealing member 10 in the upward direction in the condition where the sealing member 10 is butted to the bottom wall 4f by the pressing pins 52, 53. As such, the stretching force is removed from the sealing member 10.

As a result, the sealing member 10 tries to restore to the natural condition while the bottom surface of the sealing member 10 contacting the bottom wall 4f. Thus, the inner surfaces 12a of the sealing member 10 are brought into closely contact with the inner side wall 4d of the groove portion 4a. Accordingly, the sealing member 10 is held by the upper core plate 4.

By using the pressing jigs 52, 53, the sealing member 10 can be restored in a predetermined position with respect to the groove portion 4a. Accordingly, the sealing member 10 can be set to the upper core plate 4 at a desirable position. In the tank attaching step, the upper tank 2 is attached to the upper core plate 4 to which the sealing member 10 has been attached.

As shown in FIGS. 20 and 21, in the tank attaching step, the upper tank 2 is moved down toward the upper core plate 4 to which the sealing member 10 has been attached in a condition that the opening of the upper tank 2 defined by the outer peripheral portion 2a faces down. Thus, the end surface of the outer peripheral portion 2a is brought into contact with the sealing member 10 disposed in the groove portion 4a. Further, a predetermined pressing force is applied to the upper tank 2 such that the sealing member 10 is deformed at a predetermined compression rate.

Because the outer peripheral portion 2a is pressed against the bottom wall 4f of the groove portion 4a through the sealing member 10, the clearance between the end surface of the outer peripheral portion 2a and the bottom wall 4f of the groove portion 4a is filled with the sealing member 10. Accordingly, the upper tank 2 and the upper core plate 4 are sealed by the sealing member 10, and hence leakage of the internal fluid is restricted.

Further, the upper tank 2 is fixed to the upper core plate 4. As shown in FIG. 22, the nails 4b of the upper core plate 4 are bent inwardly over the flange portion 2c of the tank 2 in a condition where the upper tank 2 is pressed against the upper core plate 4 by the pressing force. Since the nails 4b are bent over the flange portion 2c, which expands outwardly along the outer periphery of the upper tank 2 with the outer peripheral portion 2a, the flange portion 2c is pressed from the outside. As such, the upper tank 2 is fixed to and integrated with the upper core plate 4.

Similarly, the sealing member 10 is attached to the lower core plate 5, and the lower tank 3 is attached to the lower core plate 5 in the similar manner. In this way, the radiator 1 is manufactured.

Next, effects of the method of manufacturing the radiator 1 of the present embodiment will be described. The radiator 1 is manufactured through the core plate forming step, the core section assembling step, the brazing step, the sealing member stretching step, the sealing member placing step, the sealing member attaching step and the tank attaching step.

In the core plate forming step, the core plate 4, 5 is formed into the predetermined shape having the groove portion 4a for receiving the loop-shaped sealing member 10. In the core section assembling step, the core 8 and the core plates 4, 5 are assembled, thereby to preliminarily assemble the core section.

In the brazing step, the components of the preliminarily assembled core section are brazed with one another. In the sealing member stretching step, the loop-shaped sealing member 10 is stretched into the predetermined size. In the sealing member placing step, the sealing member 10 is placed in the groove portion 4a of the core plate 4, 5 under the stretched condition.

In the sealing member attaching step, the stretching force is removed from the sealing member 10 placed in the predetermined position in the groove portion 4a to attach the sealing member 10 in the groove portion 4a in accordance with the restoration force of the sealing member 10. In the tank attaching step, the tank 2, 3 is mounted to and fixed to the core plate 4, 5 such that the connecting portion between the tank 2, 3 and the core plate 4, 5 is sealed with the sealing member 10.

In the present embodiment, the sealing member 10 having the whole length less than the whole length of the groove portion 4a under the natural condition without being elastically deformed is employed. In the sealing member attaching step, the sealing member 10 is fixed to the groove portion 4a using the restoration force, which is generated by removing the stretching force from the stretched sealing member 10.

Since the sealing member 10 having the predetermined dimension with respect to the dimension the groove portion 4a is employed, the predetermined fixing force for fixing the sealing member 10 to the groove portion 4a can be generated in accordance with the restoration force of the sealing member 10. In other words, since the sealing member 10 having the predetermined dimension is used, the sealing member 10 can be stably fixed to the core plate 4, 5. As such, the sealing member 10 can be fixed in the predetermined position in a short time. Accordingly, the radiator 1 having the sufficient sealing effect is manufactured with improved productivity.

In the core plate forming step, the core plate 4, 5 is formed to have the substantially rectangular-shaped groove portion 4a including the long-side portions 41 extending in the longitudinal direction X and the short-side portions 42 extending in the width direction Y. Further, in the sealing member attaching step, the sealing member 10 can be attached to the groove portion 4a to contact the inner side wall 4d at least at the long-side portions 41 or the short-side portions 42.

In this case, the long sides 11 or the short sides 12 of the sealing member 10 are fixed to the groove portion 4a. That is, the positioning and fixing of the sealing member 10 are conducted in consideration of the restoration force in the longitudinal direction X or the width direction Y. As such, productivity improves.

In the core plate forming step, the core plate 4, 5 is formed to have the substantially rectangular-shaped groove portion 4a including the long-side portions 41 extending in the longitudinal direction X and the short-side portions 42 extending in the width direction Y. Further, in the sealing member attaching step, the sealing member 10 can be attached to the groove portion 4a to contact the inner side wall 4d at least at the corner portions 43 where the long side portion 41 and the short-side portions 42 intersect each other.

In this case, the sealing member 10 is brought into contact with the inner side wall 4d at the corner portions 43 in accordance with the restoration force of the loop-shaped sealing member 10. Thus, the sealing member 10 having any loop shapes can be securely attached to the groove portion 4a. Also, the sealing member 10 can be stably held by the core plate 4, 5 before being pressed by the tank 2, 3.

Second Embodiment

A second embodiment of the present invention will be described with reference to FIGS. 23A to 25. In the second embodiment, the sealing structure between the tank 2, 3 and the core plate 4, 5 is modified from that of the first embodiment. Other structures of the radiator 1 are similar to those of the radiator 1 of the first embodiment. Also in the second embodiment, the sealing structure between the lower tank 3 and the lower core plate 5 is similar to the sealing structure between the upper tank 2 and the upper core plate 4, a description hereinafter will be made mainly in association with the sealing structure between the upper tank 2 and the upper core plate 4.

The upper tank 2 has the projection 2b projecting from the end surface of the outer peripheral portion 2a toward the sealing member 10. The projection 2b is formed entirely along the end surface of the outer peripheral portion 2a. The projection 2 is in the form of line or stripe having a predetermined width. The projection 2 serves to partly increase the pressing force against the surface of the sealing member 10, thereby to improve the sealing effect.

The sealing member 10 has a belt-like body portion to be received in the groove of the groove portion 4a. The projection 2b is formed on the end surface of the outer peripheral portion 2a at a position corresponding to a substantially middle portion of the width of the belt-like body of the sealing member 10 under the condition where the upper tank 2 is fixed to the upper core plate 4. (e.g., FIG. 4) Here, the term “substantially middle portion” includes “exactly middle portion” also. The projection 2b has a curved top end. For example, the projection 2b has a substantially semi-circular shape in a cross-section.

Further, similar to the example of FIG. 4, the sealing member 10 can be disposed such that the short sides 12 are closer to the inner side wall 4d than the outer side wall 4e. In other words, the sealing member 10 can be disposed such that the center of the cross-section of the short-sides 12 is located more to the inner side wall 4d than the center of the width of the short-side portion 42 of the groove portion 4a.

Further, similar to the example of FIG. 5, the groove portion 4e defines the loop-shaped groove on the inner side of the outer side wall 4e of the upper core plate 4, and the sealing member 10 is disposed entirely along the groove portion 4a. The sealing member 10 is disposed such that the inner surfaces 11a of the long sides 11 or the inner surfaces 12a of the short sides 12 contact the inner side wall 4d. Thus, it is less likely that the sealing member 10 will be displaced.

The sealing member 10 is an elastic member having a loop shape with a predetermined compression rate. The sealing member 10 has the loop-shaped body portion with the width A smaller than the width B of the groove portion 4a. (e.g., FIGS. 3 and 4) For example, the sealing member 10 is made of a rubber, such as ethylene propylene rubber (EPDM), silicon-base rubber and the like. Here, the loop shape of the sealing member 10 is not limited to a circular or annular shape, but includes any continuous shapes.

For example, the sealing member 10 is formed into a shape corresponding to the shape of each of the groove portion 4a of the upper core plate 4 and the groove portion of the lower core plate 5. That is, the sealing member 10 is formed into a shape to be adapted to the shape of the groove portion to which the sealing member 10 is attached. For example, in a case where the groove portion 4a to which the sealing member 10 is attached has a rectangular loop shape, the sealing member 10 having a rectangular loop shape can be employed. Alternatively, the sealing member 10 having another loop shape, such as a circular shape, an elliptic shape and the like, can be employed.

The sealing member 10 has an outer shape smaller than the groove portion to which the sealing member 10 is attached. For example, the whole length of the sealing member 10 under the natural condition without being affected by an external force is less than the whole length of the groove portion 4a. Here, the whole length of the sealing member 10 is defined by the whole length of the longitudinal axis of the sealing member 10 passing through the center of the cross-section of the sealing member 10. The whole length of the grove portion 4a is defined by the whole length of the longitudinal axis of the groove portion 4a passing through the middle of the width of the bottom wall 4f of the groove portion 4a.

Since the sealing member 10 has elasticity, even if the whole length of the sealing member 10 is less than the whole length of the groove portion 4a, it can be placed in the groove portion 4a while being stretched. After the sealing member 10 is placed in the groove portion 4a under the stretched condition, when the stretching force is removed from the sealing member 10, the sealing member 10 tries to return the original condition due to its restoration force and becomes in closely contact with the inner side wall 4d of the groove portion 4a. Thus, the sealing member 10 can be held in the predetermined position on the upper core plate 4.

As examples of the sealing member 10 having the rectangular loop shape with the whole length less than the whole length of the groove portion 4a under the natural condition, the sealing members 10 similar to the examples shown in FIGS. 6A and 6B can be employed.

For example, similar to the example shown in FIG. 6A, the sealing member 10 can be formed such that the width of the short-sides 12 in the width direction Y under the natural condition is less than the width of the short-side portions 42 of the groove portion 4a. In other words, the sealing member 10 is formed such that the dimension of the sealing member 10 in the width direction Y under the natural condition is less than the dimension of the groove portion 4a in the width direction Y.

In this case, the sealing member 10 can be stretched in the width direction Y such that the width of the short-sides 12 corresponds to the width of the short-side portions 42 of the groove portion 4a. Thus, the sealing member 10 contracts inwardly due to its elasticity, such as mainly in the width direction Y, as shown by arrows in FIG. 23A. Thus, the inner surfaces 11a of the long sides 11 are brought into contact with the inner side wall 4d and hence the sealing member 10 is held by the inner side wall 4a. That is, the sealing member 10 is held under the condition where the inner surfaces 11a of the long sides 11 are in contact with the inner side wall 4d of the groove portion 4a. Further, the sealing member 10 is pressed against the groove portion 4a by the outer peripheral portion 2a of the upper tank 2 under the condition where the inner surfaces 11a of the long-sides 11 are in contact with the inner side wall 4d of the groove portion 4a. As such, the sealing member 10 is fixed.

FIG. 23A shows a cross-section of the sealing member 10 when taken along a line corresponding to the line VII-VII in FIG. 5. As shown in FIG. 23A, the sealing member 10 is disposed such that the long sides 11 are located closer to the inner side wall 4d than the outer side wall 4e. In other words, the sealing member 10 is disposed such that the center of the cross-section of the long sides 11 is located more to the inner side of the core plate 4 than the center of the cross-section of the long-side portions 41 of the groove portion 4a.

In this case, the upper tank 2 has the projection 2b on the end surface of the outer peripheral portion 2a at the predetermined position so as to press against the substantially middle position of the width of the sealing member 10, as shown in FIG. 23A. That is, the projection 2b is formed at a position to substantially coincide with the line 14 passing through the center of cross-section of the sealing member 10.

As another example, similar to the example shown in FIG. 6B, the sealing member 10 can be formed such that the length of the long sides 11 in the longitudinal direction X under the natural condition is less than the length of the long-side portions 41 of the groove portion 4a. In other words, the sealing member 10 is formed such that the dimension of the sealing member 10 in the longitudinal direction X under the natural condition is less than the dimension of the groove portion 4a in the longitudinal direction X.

In this case, the sealing member 10 can be stretched in the longitudinal direction X such that the length of the long sides 11 corresponds to the length of the long-side portions 41 of the groove portion 4a. Thus, the sealing member 10 contracts inwardly, such as mainly in the longitudinal direction X, as shown by arrows in FIG. 24A. Thus, the inner surfaces 12a of the short sides 12 are brought into contact with the inner side wall 4d of the groove portion 4a and hence the sealing member 10 is held by the inner side wall 4d. Further, the sealing member 10 is pressed against the groove portion 4a by the outer peripheral portion 2a of the upper tank 2 under the condition where the inner surfaces 12a of the short-sides 12 are in contact with the inner side wall 4d. In this way, the sealing member 10 can be fixed.

FIG. 24A shows a cross-section of the sealing member 10 when taken along a line XXIVA-XXIVA in FIG. 5. As shown in FIG. 24A, the sealing member 10 is disposed such that the short sides 12 are located closer to the inner side wall 4d than the outer side wall 4e. In other words, the sealing member 10 is disposed such that the center of the cross-section of the long sides 12 is more to the inner side of the core plate 4 than the center of the cross-section of the short-side portions 42 of the groove portion 4a. Also in this case, the upper tank 2 has the projection 2b on the end surface of the outer peripheral portion 2a at the predetermined position so as to press against the substantially middle portion of the width of the sealing member 10, as shown in FIG. 24A. That is, the projection 2b is formed at a position to substantially coincide with the line 14 passing through the center of cross-section of the sealing member 10.

The sealing member 10 can be arranged in the groove portion 4a in different manners, for example, in manners shown in FIGS. 23B and 24B. FIG. 23B shows an example in which the sealing member 10 is disposed such that outer surfaces 11b of the long sides 11 contact the outer side wall 4e. FIG. 24B shows an example in which the sealing member 10 is disposed such that outer surfaces 12b of the short sides 12 contact the outer side wall 4e.

In these examples, the sealing member 10 is held by the upper core plate 4 in a condition where the inner surfaces 11a of the long sides 11 or the inner surfaces 12a of the short sides 12 are in contact with the inner side wall 4d of the groove portion 4a. Further, the sealing member 10 is fixed by being pressed against the groove portion 4a by the outer peripheral portion 2a under the condition where the inner surfaces 11a or the inner surfaces 12a are in contact with the inner side wall 4d.

In the examples of the FIG. 23B and FIG. 24B, the sealing member 10 is disposed such that the long sides 11 or the short sides 12 are located closer to the outer side wall 4e than the inner side wall 4d. In other words, the center of cross-section of the sealing member 10 is located more to the outer side than the center of the width of the groove portion 4a. Also in these cases, the projection 2b is formed on the end surface of the outer peripheral portion 2a at the predetermined position to press against the substantially middle portion of the width of the sealing member 10. That is, the projection 2b is formed at a position to substantially coincide with the line 14 passing through the center of cross-section of the sealing member 10.

The sealing member 10 is held in the predetermined position with respect to the groove portion 4a. In this condition, the substantially middle portion of the width of the sealing member 10 is pressed by the projection 2b. Thus, the sealing member 10 exhibits a repellent force equal to or greater than a predetermined degree. As such, the sealing member 10 can seal the clearance between the inner side wall 4d and the bottom wall 4f and the outer peripheral portion 2a of the upper tank 2 without being displaced during the assembling of the radiator 1. Accordingly, the sufficient sealing effect can be achieved.

FIG. 25 shows an example in which a portion of the sealing member 10 is disposed in the groove portion 4a without contacting the inner side wall 4d and the outer side wall 4e. In the case where the sealing member 10 is held in the condition where the inner surfaces 11a of the long sides 11 are in contact with the inner side wall 4d, it is not always necessary that the inner surfaces 12a of the short sides 12 are in contact with the inner side wall 4d. Likewise, in the case where the sealing member 10 is held in the condition where the inner surfaces 12a of the short sides 12 are in contact with the inner side wall 4d, it is not always necessary that the inner surfaces 11a of the long sides 11 are in contact with the inner side wall 4d. Also in these cases, the projection 2b of the upper tank 2 is formed on the end surface of the outer peripheral portion 2a at the predetermined position to press against the substantially middle portion of the width of the sealing member 10. That is, the projection 2b is formed at the position to substantially coincide with the line 14 passing through the center of cross-section of the sealing member 10.

As discussed above, at least one of the long sides 11 and the short sides 12 is in contact with at least one of the inner side wall 4d and the outer side wall 4e of the upper core plate 4. In this way, the sealing member 10 is positioned with respect to the upper core plate 4, and is held on the upper core plate 4.

Hereinafter, advantageous effects of the present embodiment will be described. The sealing member 10 is held in the deformed condition due to the pressing force from the upper tank 2, thereby to seal the connecting portion between the upper tank 2 and the upper core plate 4. The sealing member 10 has the belt-like loop-shaped body portion having the width A smaller than the width B of the groove portion 4a, and has elasticity. The body portion of the sealing member 10 is positioned with respect to the upper core plate 4 under the condition of contacting at least one of the inner side wall 4d and the outer side wall 4e. In the condition where the upper tank 2 is fixed to the upper core plate 4, the projection 2b presses against the substantially middle portion of the width of the body portion of the sealing member 10.

In this configuration, the sealing member 10 is held under the predetermined position with respect to the groove portion 4a, and the middle position of the width of the sealing member 10 is pressed by the projections 2b. Therefore, the pressing force from the upper tank 2 can be sufficiently transmitted to the sealing member 10. As such, the sealing member 10 can be securely and sufficiently compressed. That is, the sealing member 10 can sufficiently generate the elastic force against the upper core plate 4 and the upper tank 2. Accordingly, the sufficient sealing effect is achieved.

The groove portion 4a has the substantially rectangular-shaped groove including the pair of long-side portions 41 and the pair of short-side portions intersecting the long-side portions 41 through the corner portions 43. The sealing member 10 is attached to the upper core plate 4 under the condition of contacting the inner side wall 4d or the outer side wall 4e of the groove portion 4a in the long-side portions 41 or the short-side portions 42 due to the elasticity.

In this case, the sealing member 10 is positioned to and fixed to the groove portion 4a at one of the long sides 11 and the short sides 12 due to its elasticity. Therefore, the positioning and fixing of the sealing member 10 with respect to the upper core plate 4 can be conducted by considering the restoration force in one of the longitudinal direction X and the width direction Y. Accordingly, the productivity further improves.

The sealing member 10 is configured such that the whole length thereof is less than the whole length of the groove portion 4a under the natural condition without being elastically deformed.

That is, the sealing member 10 having a predetermined dimension with respect to the groove portion 4a is prepared. Then, the sealing member 10 is stretched into the predetermined size and fixed to the groove portion 4a using its restoration force. Therefore, the sealing member 10 is fixed to the groove portion 4a with the fixing force generated in accordance with the restoration force. It is less likely that the sealing member 10 will be easily displaced during the manufacturing process. Accordingly, the radiator 1 in which the sealing member 10 can be fixed in the predetermined position with a simple structure can be provided. In this case, since the sealing member 10 can be held by the upper core plate 4, arrangement or assembling directions of the radiator 1 during the manufacturing process is not limited. The dimension of the sealing member 10 can be determined in consideration of workability on attaching to the groove portion 4a and the compression rate of the sealing member 10. Thus, the sealing effect of the sealing member 10 improves while improving the productivity.

In the case where the sealing member 10 is pressed by the tank 2 under the condition where the short-sides 42 are in contact with the inner side wall 4d of the groove portion 4a by the restoration force, the contact area with the sealing member 10 and the inner side wall 4d is reduced. In this case, therefore, a surface pressure applied to the sealing member 10 can be increased. As such, the fixing force of the sealing member 10 is ensured, and thus the sealing member 10 is more stably fixed in the predetermined position.

In the case where the rectangular loop-shaped sealing member 10 including the pair of long sides 11 and the pair of short sides 12 is employed, the sealing member 10 is, for example, formed such that the pair of long sides 11 are shorter than the long-side portions 41 of the groove portion 4a under the natural condition. In this case, the sealing member 10 is placed in the groove portion 4a while being stretched in the longitudinal direction X. Thus, the sealing member 10 is fixed to the groove portion 4a using the restoration force in the longitudinal direction X. Accordingly, the positioning of the sealing member 10 with respect to the groove portion 4a is easily conducted, and fixing work of the sealing member 10 improves.

In the case where the rectangular loop-shaped sealing member 10 including the pair of long sides 11 and the pair of short sides 12 is employed, the sealing member 10 is, for example, formed such that the pair of short sides 12 are shorter than the pair of short-side portions 42 of the groove portion 4a under the natural condition. In this case, the sealing member 10 is placed in the groove portion 4a while being stretched in the width direction Y. Thus, the sealing member 10 is fixed to the groove portion 4a using the restoration force in the width direction Y. Accordingly, the positioning of the sealing member 10 with respect to the groove portion 4a is easily conducted, and fixing work of the sealing member 10 improves.

In the case where the groove portion 4a includes the bottom wall 4f, the outer side wall 4e extending perpendicularly from the bottom wall 4f, and the inner side wall 4d extending perpendicularly from the bottom wall 4f and opposed to the outer side wall 4e, it has the substantially U-shape in a cross-section. In this case, the sealing member 10 can easily contact inner surfaces of the groove portion 4a. Thus, the sealing member 10 can be stably disposed in the groove portion 4a.

In the case where the sealing member 10 having the rectangular cross-sectional shape is employed, the contact area of the sealing member 10 with the groove portion 4a increases. Therefore, the fixing condition of the sealing member 10 on the upper core plate 4 before being pressed by the tank 2 becomes stable and thus the sealing member 10 can be easily arranged in the predetermined position.

In the case where the projection 2b of the upper tank 2 has the curved surface at the top end, even if the sealing member 10 is directly pressed by the curved surface of the projection 2b, it is less likely that pressure will be locally applied to the sealing member 10. As such, damage to the sealing member 10 can be reduced. With this, it is possible to sufficiently apply the pressing force to the sealing member 10.

Next, a method of manufacturing the radiator 1 of the second embodiment will be described. The method generally includes a core plate forming step, a core section assembling step, a brazing step, a sealing member attaching step and a tank attaching step. The sealing member attaching step includes a sealing member stretching step and a sealing member placing step.

The lower core plate 5 has the similar structure as the upper core plate 4, and the sealing structure between the lower core plate 5 and the lower tank 3 is similar to that between the upper core plate 4 and the upper tank 2. Therefore, the method will be hereinafter described mainly in association with the upper core plate 4.

In the second embodiment, the core plate forming step, the core section assembling step, and the brazing step are performed in the similar manner as those of the first embodiment. Thus, the description thereof is not repeated.

In the sealing member attaching step, the sealing member 10 is disposed in a predetermined position in the groove portion 4a such that the sealing member 10 contacts at least one of the inner side wall 4d and the outer side wall 4e. Here, an example of the sealing member attaching step in which the sealing member 10 is attached to contact the inner side wall 4d of the groove portion 4a through the sealing member stretching step and the sealing member placing step will be described.

First, in the sealing member stretching step, the sealing member 10, which has been formed into the predetermined shape, for example as shown in FIG. 14, is stretched into a predetermined size. For example, the sealing member 10 has been formed such that the whole length is less than the whole length of the groove portion 4a, and the dimension Lp is less than the dimension L of the groove portion 4a with respect to the longitudinal direction X. The sealing member 10 having the above shape is stretched and attached to the upper tank 2 in the similar manner as those of the first embodiment shown in FIGS. 15 to 19.

In the tank attaching step, the upper tank 2 is attached to the upper core plate 4 to which the sealing member 10 has been attached.

In the tank attaching step, the upper tank 2 is arranged such that the opening defined by the outer peripheral portion 2a faces down and moved down toward the upper core plate 4 to which the sealing member 10 has been attached, in the similar manner as shown in FIGS. 20 and 21. Thus, the end surface of the outer peripheral portion 2a is brought into contact with the sealing member 10 disposed in the groove portion 4a.

In this case, the projection 2b of the upper tank 2 is brought into contact with the substantially middle portion of the width of the sealing member 10 in the groove portion 4a. Further, a predetermined pressing force is applied to the upper tank 2 such that the sealing member 10 is deformed at a predetermined compression rate. Thus, the sealing member 10 is deformed by being pressed by the projection 2b while generating a sufficient elastic force. As such, the clearance between the outer peripheral portion 2a and the bottom wall 4f of the groove portion 4a is sealed with the deformed sealing member 10. Accordingly, leakage of the cooling water is restricted.

Further, the upper tank 2 is fixed to the upper core plate 4, in the similar manner as shown in FIG. 22.

The sealing member 10 is attached to the lower core plate 5, in the similar manner as that of the upper core plate 4. Also, the lower tank 3 is attached to the lower core plate 5, in the similar manners as that of the upper tank 2. In this way, the radiator 1 is manufactured.

Next, effects of the method of manufacturing the radiator 1 of the present embodiment will be described. The method includes the core plate forming step, the core section assembling step, the brazing step, the sealing member attaching step and the tank attaching step.

In the core plate forming step, the core plate 4, 5 is formed into the predetermined shape having the groove portion 4a for receiving the loop-shaped sealing member 10. In the core section assembling step, the core part 8 and the core plates 4, 5 are assembled, thereby to preliminarily assemble the core section. In the brazing step, the components of the preliminarily assembled core section are brazed with one another.

In the sealing member attaching step, the sealing member 10 is positioned to the groove portion 4a such that the sealing member 10 contacts at least one of the inner side wall 4d and the outer side wall 4e. Thus, the sealing member 10 is attached to the groove portion 4a.

In the tank attaching step, the tank 2, 3 is mounted to and fixed to the core plate 4, 5 such that the connecting portion between the tank 2, 3 and the core plate 4, 5 is sealed with the sealing member 10. Further, in the tank attaching step, the tank 2, 3 is set to the core plate 4, 5 so that the projection 2b of the tank 2, 3 buts to the substantially middle portion of the width of the sealing member 10. In this condition, the predetermined pressing force is applied to the sealing member 10 through the tank 2, 3.

In this case, the sealing member 10, which has been set to the predetermined position in the groove portion 4a, is elastically deformed by pressing the substantially middle portion of the width of the sealing member 10 by the projection 2b of the tank 2, 3. Therefore, the pressing force is sufficiently transmitted to the sealing member 10, and the sealing member 10 can be properly and sufficiently compressed. Accordingly, the manufacturing method which can fix the sealing member 10 in the predetermined position and exhibit the sufficient sealing effect can be achieved.

In the core plate forming step, the core plate 4, 5 is formed to have the substantially rectangular loop-shaped groove portion 4a including the long-side portions 41 extending in the longitudinal direction X and the short-side portions 42 extending in the width direction Y. Further, in the sealing member attaching step, the sealing member 10 is attached to the groove portion 4a such that the sealing member 10 contact with the inner side wall 4d at least at the long-side portions 41 or the short-side portions 42.

In this case, the long sides 11 or the short sides 12 of the sealing member 10 are fixed to the groove portion 4a. That is, the positioning and fixing work of the sealing member 10 can be conduced in consideration of the restoration force in one of the longitudinal direction X or the width direction Y. As such, productivity improves. In other words, the sealing member 10 constricts the inner side wall 4d at least at two opposite locations due to its elastic force. In this condition, the sealing member 10 exerts a predetermined constriction force to the core plate 4 without being separated from the core plate 4. Thus, the sealing member 10 is held by the core plate 4. Accordingly, the sealing member 10 is securely fixed in the predetermined position between the upper tank 2 and the upper core plate 4, thereby to achieve the sufficient sealing effect. The sealing between the lower core plate 5 and the lower tank 3 can be provided in the similar manner, and thus the same effects are achieved.

In the present embodiment, the whole length of the sealing member 10 under the natural condition without being elastically deformed is less than the whole length of the groove portion 4a. In the sealing member attaching step, the sealing member 10 is fixed to the groove portion 4a using the restoration force of the sealing member 10, which is generated by removing the stretching force from the sealing member 10.

Since the sealing member 10 having the predetermined dimension with respect to the groove portion 4a is employed, the predetermined fixing force for fixing the sealing member 10 to the groove portion 4a can be generated in accordance with the restoration force of the sealing member 10. In other words, since the sealing member 10 having the predetermined dimension is used, it can be stably fixed to the core plate 4, 5. As such, the sealing member 10 can be smoothly fixed in the predetermined position. Accordingly, the manufacturing method achieves the sufficient sealing effect and enhances productivity.

In the core plate forming step, the core plate 4, 5 is formed to have the substantially rectangular loop-shaped groove portion 4a including the long-side portions 41 extending in the longitudinal direction X and the short-side portions 42 extending in the width direction Y. Further, in the sealing member attaching step, the sealing member 10 can be attached to the groove portion 4a such that the sealing member 10 contacts the inner side wall 4d at least at the corner portions 43 where the long side portion 41 and the short-side portions 42 intersect each other.

In this case, the sealing member 10 is brought into contact with the inner side wall 4d at the corner portions 43 in accordance with the restoration force of the loop-shaped sealing member 10. Thus, the sealing member 10 having any looped shapes can be securely attached to the groove portion 4a. Also, the sealing member 10 can be stably held by the core plate 4, 5 even before being pressed by the tank 2, 3.

In the sealing member attaching step, the sealing member 10 is stretched into the predetermined size, and then the stretched sealing member 10 is placed in the groove portion 4a of the core plate 4, 5. Thereafter, the stretching, force is removed from the sealing member 10. As such, the sealing member 10 is attached to the groove portion 4a in accordance with the restoration of the sealing member 10.

In this case, the sealing member 10 is brought into contact with the inner side wall 4d of the groove portion 4a in accordance with the degree of contraction of the sealing member 10 from the predetermined size. That is, the fixing force for fixing the sealing member 10 can be obtained by a simple process. Further, the sealing member 10 can be efficiently attached to the core plate 4, 5.

Third Embodiment

A third embodiment of the present invention will be hereinafter described with reference to FIGS. 26 to 28. In the third embodiment, the sealing member 10 is modified from that of the second embodiment, and an example in which the sealing member 10 is attached to the core plate 4, 5 while contacting the outer side wall 4e will be described. FIG. 26 shows a sealing member 10B employed in the third embodiment. FIG. 27 shows an upper core plate 40 employed in the third embodiment. The core plate 40 and the sealing member 10B have structures different from the core plate 4 and the sealing member 10 of the second embodiments. The lower core plate has the similar structure as the upper core plate 40. Also, like parts are designated with the like reference numerals. Structures of the radiator 1 other than the core plate 40 and the sealing member 10B are similar to those of the second embodiment. Thus, similar effects can be achieved.

As shown in FIG. 26, the sealing member 10B has the belt-like body portion, hook portions 15 and neck portions 16. The body portion, for example, has the substantially rectangular loop shape including the pair of long sides 11 and the pair of short sides 12, similar to the second embodiment.

The hook portions 15 project outwardly from the outer surfaces 11b, 12b of the body portion through the neck portions 16. Each of the hook portions 15 has a shape along the body portion. The hook portion 15 is a hook piece having a predetermined length. Specifically, the hook portion 15 is spaced from the outer surface 11b, 12b through the neck portion 16. In other words, the hook portion 15 is connected to the body portion through the neck portion 16. The sealing member 10B has multiple hook portions 15.

For example, three hook portions 15 are provided along each of the long sides 11 of the body portion at predetermined intervals, and one hook portion 15 is provided on each of the short sides 12 of the body portion. The body portion, the hook portions 15 and the neck portions 16 of the sealing member 10B are made of the same material, such as EPDM, silicon-base rubber and the like. The body portion, the hook portions 15 and the neck portions 16 are integrally formed with one another using a die.

As shown in FIGS. 27 and 28, the upper core plate 40 has the groove portion 4a defining the substantially rectangular loop-shaped groove, similar to the upper core plate 4 of the second embodiment. Further, the upper core plate 40 has multiple slits 45 on the outer side wall 4e of the groove portion 4a. Each of the slits 45 has a predetermined width. The slits 45 are formed at locations corresponding to the neck portions 16 of the sealing member 10B. Each of the slit 45 is formed into a notch having a dimension larger than the width of the neck portion 16 for receiving the neck portion 16.

In the present, embodiment, the hook portions 15 are hooked on the outer side wall 4e by fitting the neck portions 16 into the slits 45, and hence the sealing member 10B is fixed to the upper core plate 40. In this case, the sealing member 10B receives a tensile force in an outward direction. Thus, the sealing member 10B is held on the upper core plate 40 under a condition where at least one of the outer surfaces 11b and the outer surfaces 12b of the body portion is in contact with the outer side wall 4e.

Further, as shown in FIG. 28, the upper tank 2 has the projection 2b at a position corresponding to the substantially middle portion of the width of the body portion of the sealing member 10B. That is, the projection 2b is formed on the end surface of the outer peripheral portion 2a to substantially coincide with the line passing through the center of the cross-section of the body portion. Thus, the projection 2b is pressed against the substantially middle portion of the width of the sealing member 10B. Accordingly, the upper tank 2 can apply the predetermined pressing force to the sealing member 10B, thereby to ensure the sealing effect.

In this case, a clearance is easily provided between the inner surface 11a, 12a and the inner side wall 4d of the groove portion 4a. Therefore, the sealing member 10B can be easily fixed to the groove portion 4a. Accordingly, productivity improves. Furthermore, since the sealing member 10B is located closer to the outer side wall 4e in the groove portion 4a, the sealing structure having sufficient strength against internal pressure of the upper tank 2 can be achieved.

Other Embodiments

Various exemplarily embodiments of the present invention are described hereinabove. However, the present invention is not limited to the above described exemplary embodiments, but may be implemented in various other ways without departing from the spirit of the invention. Further, the present invention can be implemented by combining the above exemplary embodiments in various ways. Furthermore, the present invention can be implemented by appropriately combining portions of the above exemplary embodiments in various ways.

In the above-discussed methods of manufacturing the radiator according to the first and second embodiments, the sealing member 10 in which the dimension Lp under the natural condition is less than the dimension L of the groove portion 4a with respect to the longitudinal direction X is employed. The sealing member 10 is placed in the groove portion 4a under the condition of being stretched into the predetermined length, such as the length L, in the longitudinal direction X, and is then fixed to the upper core plate 4 using the restoration (contraction) force.

Alternatively, the sealing member 10 as shown in FIG. 6A can be employed in the above-discussed methods. The sealing member 10 shown in FIG. 6A has the width Dp under the natural condition less than the width D of the groove portion 4a with respect to the width direction Y. In this case, the sealing member 10 is stretched into the predetermined width, such as the width D, in the width direction D. The sealing member 10 is placed in the groove portion 4a under the stretched condition. When the stretching force is removed from the sealing member 10, the sealing member 10 contracts. In this way, the sealing member 10 can be fixed to the upper core plate 4 using the restoration (contraction) force of the sealing member 10 in the width direction Y. In this case, the inner surfaces 11a of the long sides 11 of the sealing member 10 contact the inner side wall 4d of the groove portion 4a. Therefore, the sealing member 10 can be fixed in the predetermined position through the inner surfaces 11a. Accordingly, the sealing member 10 can be properly held by the upper core plate 4.

As another example, in a case where the sealing member 10 having the whole length less than the whole length of the groove portion 4a is employed, the sealing member 10 can be stretched in both the longitudinal direction X and the width direction Y into the predetermined dimensions. The sealing member 10 is placed in the groove portion 4a under the stretched condition. When the stretching force is removed, the sealing member 10 contracts in the longitudinal direction X and the width direction Y. Accordingly, the sealing member 10 can be fixed to the upper core plate 4 using the contraction force in the longitudinal direction X and the width direction Y.

In the second embodiment, the sealing member 10 can be disposed such that the inner surfaces of the corner portions 13 thereof closely contact the inner side wall 4d by contracting inwardly at the four corner portions 13. Thus, the sealing member 10 is held at the corner portions 13. Further, the sealing member 10 is fixed by being pressed against the groove portion 4a by the outer peripheral portion 2a under the condition where the inner surfaces of the corner portions 13 are in contact with the inner side wall 4d.

In this case, the corner portions 13 of the sealing member 10 are disposed closer to the inner side wall 4d than the outer side wall 4e. In other words, the sealing member 10 is disposed such that the longitudinal axis at the corner portions 13 is located more to the inner side of the upper core plate 4 than the longitudinal axis of the groove portion 4a at the corner portions 43. In this case, the corner portions 13 of the loop-shaped sealing member 10 can be brought into contact with the corner portions 43 of the groove portion 4a. Thus, any loop-shaped sealing member, other than the rectangular-shaped sealing member, can be properly fixed to the groove portion 4a.

To make the sealing member 10 to contact the inner side wall 4d of the groove portion 4a at the corner portions 13, for example, the sealing member 10 can be formed such that a radius of curvature of the inner surface of the corner portion 13 is greater than a radius of curvature of the inner side wall 4d of the corner portion under the natural condition. After such sealing member 10 is stretched and placed in the groove portion 4a under the stretched condition, when the stretching force is removed, the sealing member 10 contracts inwardly due to the restoration force for restoring to the original condition. In this case, the inner surfaces of the corner portions 13 are brought into contact with the corner portions of the inner side wall 4d prior to the other portions. Thus, the sealing member 10 can be held by the upper core plate 4 in accordance with the close contact at the corner portions 13.

Additional advantages and modifications will readily occur to those skilled in the art. The invention in its broader term is therefore not limited to the specific details, representative apparatus, and illustrative examples shown and described.

Claims

1. A heat exchanger comprising: a core including a plurality of tubes;a core plate connected to the tubes;a tank connected to the core plate to be in communication with the tubes; anda sealing member having a loop shape and disposed to seal a connecting portion between the core plate and the tank, whereinthe core plate has a groove portion including at least a base wall and an inner side wall to define a groove having a loop shape, andthe sealing member is disposed in the groove portion and is in contact with the inner side wall at least at two opposite locations of the loop shape.

2. The heat exchanger according to claim 1, wherein the groove portion defines the groove in a form of substantially rectangular loop including a pair of long-side portions extending in a longitudinal direction of the core plate and a pair of short-side portions intersecting the long-side portions, andthe sealing member is pressed against the core plate by the tank under a condition where the sealing member is in contact with the inner side wall in at least one of the long-side portions and the short-side portions in accordance with a restoration force, which is generated by restoring the sealing member from a stretched condition.

3. The heat exchanger according to claim 1, wherein the groove portion defines the groove in a form of substantially rectangular loop including a pair of long-side portions extending in a longitudinal direction of the core plate and a pair of short-side portions intersecting the long-side portions through corner portions, andthe sealing member is pressed against the core plate by the tank under a condition where the sealing member is in contact with the inner side wall in the corner portions in accordance with a restoration force, which is generated by restoring the sealing member from a stretched condition.

4. The heat exchanger according to claim 1, wherein the groove portion defines the groove in a form of substantially rectangular loop including a pair of long-side portions extending in a longitudinal direction of the core plate and a pair of short-side portions intersecting the long-side portions,the sealing member has a substantially rectangular shape including a pair of long sides and a pair of short sides intersecting the long sides, andthe sealing member is configured to satisfy at least one of a first shape condition in which the long sides are shorter than the long-side portions and a second shape condition in which the short sides are shorter than the short-side portions, under an original condition without being elastically deformed

5. The heat exchanger according to claim 1, wherein the sealing member is fixed to the groove portion such that a center of a cross-section defined perpendicular to a longitudinal axis thereof is closer to the inner side wall than a center of cross-section of the groove portion.

6. The heat exchanger according to claim 1, wherein the groove portion further includes an outer side wall extending perpendicularly from the bottom wall,the inner side wall perpendicularly extends from the bottom wall and is spaced from the outer side wall, andthe groove is defined by the inner side wall, the bottom wall and the outer side wall.

7. The heat exchanger according to claim 1, wherein the groove of the groove portion has a depth equal to or greater than a thickness of the sealing member.

8. The heat exchanger according to claim 1, wherein the sealing member has a substantially rectangular cross-section.

9. The heat exchanger according to claim 1, wherein the sealing member is arranged in the groove portion to contact only the inner side wall.

10. A heat exchanger comprising: a core including a plurality of tubes;a core plate connected to the tubes;a tank connected to the core plate to be in communication with the tubes; anda sealing member having a loop shape and disposed to seal a connecting portion between the core plate and the tank, whereinthe core plate has a groove portion including at least a base wall and an inner side wall to define a groove having a loop shape,the sealing member has a width smaller than a width of the groove of the groove portion and is configured such that a whole length thereof under an original condition without being elastically deformed is less than a whole length of the groove, the whole length of the sealing member being defined by a whole length of a longitudinal axis passing through a center of a cross-section of the sealing member, the whole length of the groove being defined by a whole length of a longitudinal axis passing through a center of the width of the groove, andthe sealing member is fixed to the groove portion in accordance with a restoration force, which is generated by restoring the sealing member from a stretched condition, andthe sealing member is further pressed against the groove portion by the tank.

11. The heat exchanger according to claim 10, wherein the groove portion defines the groove in a form of substantially rectangular loop including a pair of long-side portions extending in a longitudinal direction of the core plate and a pair of short-side portions intersecting the long-side portions, andthe sealing member is pressed against the core plate by the tank under a condition where the sealing member is in contact with the inner side wall in at least one of the long-side portions and the short-side portions in accordance with the restoration force thereof.

12. The heat exchanger according to claim 11, wherein the groove portion defines the groove in a form of substantially rectangular loop including a pair of long-side portions extending in a longitudinal direction of the core plate and a pair of short-side portions intersecting the long-side portions through corner portions, andthe sealing member is pressed against the core plate by the tank under a condition where the sealing member is in contact with the inner side wall in the corner portions in accordance with the restoration force thereof.

13. The heat exchanger according to clam 11, wherein the groove portion defines the groove in a form of substantially rectangular loop including a pair of long-side portions extending in a longitudinal direction of the core plate and a pair of short-side portions intersecting the long-side portions,the sealing member has a substantially rectangular shape including a pair of long sides and a pair of short sides intersecting the long sides, andthe sealing member is configured to satisfy at least one of a first shape condition in which the long sides are shorter than the long-side portions and a second shape condition in which the short sides are shorter than the short-side portions, under the original condition without being elastically deformed.

14. The heat exchanger according to claim 11, wherein the sealing member is fixed to the groove portion such that a center of cross-section defined perpendicular to a longitudinal axis thereof is closer to the inner side wall than a center of cross-section of the groove portion.

15. The heat exchanger according to claim 11, wherein the groove portion further includes an outer side wall extending perpendicularly from the bottom wall,the inner side wall perpendicularly extends from the bottom wall and is spaced from the outer side wall, andthe groove is defined by the inner side wall, the bottom wall and the outer side wall.

16. The heat exchanger according to claim 11, wherein the groove of the groove portion has a depth equal to or greater than a thickness of the sealing member.

17. The heat exchanger according to claim 11, wherein the sealing member has a substantially rectangular cross-section.

18. The heat exchanger according to claim 1, wherein the sealing member is arranged in the groove portion to contact only the inner side wall.

19. A method of manufacturing a heat exchanger comprising: forming a core plate into a predetermined shape including a groove portion defining a loop-shaped groove;assembling the core plate to tubes;preparing a sealing member having a whole length less than a whole length of the groove, the whole length of the sealing member being defined by a whole length of a longitudinal axis passing through a center of a cross-section of the sealing member, the whole length of the groove being defined by a whole length of a longitudinal axis passing through a center of a width of the groove;stretching the sealing member into a predetermined size;placing the sealing member under a stretched condition in the groove portion;attaching the sealing member to the groove portion in accordance with a restoration force caused by removing a stretching force from the sealing member; andfixing a tank to the core plate such that the sealing member is elastically deformed between the tank and the core plate.

20. The method according to claim 19, wherein the groove of the core plate has a substantially rectangular shape including a pair of long-side portions and a pair of short-side portions intersecting the long-side portions, andthe attaching includes bringing the sealing member into contact with an inner side wall of the groove portion in at least one of the long-side portions and the short-side portions.

21. The method according to claim 19, wherein the groove of the core plate has a substantially rectangular shape including a pair of long-side portions and a pair of short-side portions intersecting the long-side portions through corner portions, andthe attaching includes bringing the sealing member into contact with an inner side wall of the groove portion at the corner portions.

22. The method according to claim 19, wherein the attaching includes pressing the stretched sealing member against a base wall of the groove portion by a pressing jig, andthe stretching force is removed from the sealing member during the pressing.

23. A heat exchanger comprising: a core including a plurality of tubes;a core plate connected to the tubes, the core plate having a groove portion including an inner side wall and an outer side wall to define a loop-shaped groove therebetween;a tank connected to the core plate to be in communication with the tubes; anda sealing member sealing between the core plate and the tank, whereinthe sealing member has a loop-shaped body portion having a width less than a width of the groove,the body portion of the sealing member is disposed in the groove portion under a condition of being in contact with at least one of the inner side wall and the outer side wall,the tank has a projection on an end surface opposing to the body portion, andthe projection presses against a substantially middle portion of the width of the body portion to elastically deform the body portion.

24. The heat exchanger according to claim 23, wherein the groove portion defines the groove in a form of substantially rectangular loop including a pair of long-side portions extending in a longitudinal direction of the core plate and a pair of short-side portions intersecting the long-side portions,the body portion of the sealing member is in contact with one of the inner side wall and the outer side wall at one of the long-side portions and the short-side portions.

25. The heat exchanger according to claim 23, wherein the body portion of the sealing member has a whole length less than a whole length of the groove under an original condition without being elastically deformed, the whole length of the body portion being defined by a length of a longitudinal axis passing through a center of a cross-section of the body portion, the whole length of the groove being defined by a whole length of a longitudinal axis passing through a center of the width of the groove, andthe body portion is in contact with the inner side wall in accordance with a restoration force, which is generated by restoring the body portion from a stretched condition.

26. The heat exchanger according to claim 23, wherein the sealing member has a hook portion projecting from an outer surface of the body portion,the hook portion is hooked on the outer side wall of the groove portion such that the body portion of the sealing member is in contact with the outer side wall of the groove portion.

27. The heat exchanger according to claim 23, wherein the body portion of the sealing member has a rectangular cross-section.

28. The heat exchanger according to claim 23, wherein the projection has a curved end surface.

29. A method of manufacturing a heat exchanger, comprising: forming a core plate into a predetermined shape including a groove portion defining a loop-shaped groove;assembling the core plate to tubes;attaching a sealing member in the groove portion such that the sealing member contacts at least one of an inner side wall and an outer side wall of the groove portion; andfixing a tank to the core plate such that a projection of an end surface of the tank is pressed against a substantially middle portion of a width of the sealing member to elastically deform the sealing member, thereby sealing between the core plate and the tank with the sealing member.

30. The method according to claim 29, wherein the groove has a substantially rectangular shape including a pair of long-side portions extending in a longitudinal direction of the core plate and a pair of short-side portions intersecting the long-side portions, andthe attaching includes bringing the sealing member into contact with the inner side wall in at least one of the short-side portions and the long-side portions.

31. The method according to claim 29, wherein the attaching includes stretching the sealing member into a predetermined size, placing the sealing member in the groove under a stretched condition, and removing a stretching force from the sealing member, thereby to bring the sealing member into contact with the inner side wall in accordance with a restoration force thereof.

32. The method according to claim 29, further comprising: preparing the sealing member having a whole length less than a whole length of the groove under an original condition without being elastically deformed, the whole length of the sealing member being defined by a whole length of a longitudinal axis passing through a center of a cross-section of the sealing member, the whole length of the groove being defined by a whole length of a longitudinal axis passing through a center of a width of a groove defined by the groove portion, whereinthe attaching includes stretching the sealing member into a predetermined size and fixing the sealing member to the groove portion in accordance with a restoration force caused by removing a stretching force from a stretched sealing member.